Add PSS::RemoveClientFromServer() and call it on STOP_SYNC shutdowns.

When sync is disabled on a device, we need to notify the server that
the client is no longer active.

BUG=419552

Review URL: https://codereview.chromium.org/864993002

Cr-Commit-Position: refs/heads/master@{#317236}

1 files changed, 18 insertions, 0 deletions

diff --git a/sync/protocol/sync.proto b/sync/protocol/sync.proto
index 2c79c22..78f9d40 100644
--- a/sync/protocol/sync.proto
+++ b/sync/protocol/sync.proto
@@ -976,3 +976,21 @@ message ClientToServerResponse {
   // sent with any subsequent ClientToServerMessages.
   optional ChipBag new_bag_of_chips = 14;
 };
+
+// A message to notify the server of certain sync events. Idempotent. Send these
+// to the /event endpoint.
+message EventRequest {
+  optional SyncDisabledEvent sync_disabled = 1;
+};
+
+message EventResponse {
+};
+
+// A message indicating that the sync engine has been disabled on a client.
+message SyncDisabledEvent {
+  // The GUID that identifies the sync client.
+  optional string cache_guid = 1;
+
+  // The store birthday that the client was using before disabling sync.
+  optional string store_birthday = 2;
+};